1. Field of the Invention
The invention relates to an exercise bicycle, more particularly to an improved arm lever construction for an exercise bicycle,
2. Description of the Related Art
Referring to FIG. 1, a conventional exercise bicycle 10 is shown to comprise a frame 11, a foot pedal assembly 12, a reciprocating arm assembly 13, a resistance wheel 14, and a transmission system 15.
The transmission system 15 includes a drive shaft 121 mounted rotatably on a rear end portion of the frame 11, and a pair of eccentric arms 122 mounted securely on two ends of the drive shaft 121 (only one eccentric arm 122 is shown). The foot pedal assembly 12 includes a pair of foot pedal cranks 123 mounted on a distal end of a respective one of the eccentric arms 122 (only one foot pedal crank 123 is shown). The reciprocating arm assembly 13 includes a pair of reciprocating arm levers 131 mounted pivotally on a front end portion of the frame 11 on two sides of the latter, and a pair of crank arms 132 (only one of the arm levers 131 and the crank arms 132 is shown). Each of the crank arms 132 has a first end connected to the distal end of a respective one of the eccentric arms 122 and a second end connected pivotally to a lower end of a respective one of the arm levers 131. Thus, operation of the foot pedal cranks 123 results in forward and rearward movement of the crank arms 132 to produce reciprocating movement of the arm levers 131.
The resistance wheel 14 is mounted rotatably on the front end portion of the frame 11 between the arm levers 131. The transmission system 15 is used to link the foot pedal cranks 123 to the resistance wheel 14, thus permitting the rotation of the resistance wheel 14 when the foot pedal cranks 123 are operated. When the arm levers 131 are oscillated, the crank arms 132 cause the drive shaft 121 to rotate, thereby similarly driving the transmission system 15 to rotate the resistance wheel 14. The conventional exercise bicycle can thus be used to exercise the upper and lower parts of the body. Referring to FIG. 2, the range of pivoting movement of the arm levers 131 is fixed and cannot be varied so as to suit the physique of the user. For example, if the user has long hands, it is quite possible that the hands of the user are not fully stretched when the arm levers 131 reach the front limit of the pivoting range. This often results in fatigue, poor exercise results and can affect the user's interest in using the conventional exercise bicycle 10. If the user has short hands, it is possible that the user has to lean forward in order to move the arm levers 131 to the front limit of the pivoting range. This can also cause the user to tire easily.